He was told by Judge Andrew Bright QC at St Albans Crown Court that had the offences been committed under modern sentencing guidelines, he would have received a much longer term.

Prosecutor Helen Guest said that, at the time, Jackson was aged 24 to 26. He had been due to stand trial, but changed his plea to guilty on 9 November. Sentence was adjourned then for reports.

His barrister Anita Aurora said he had been due to be sentenced earlier this month, but had been taken to hospital after trying to kill himself with a paracetamol overdose.

The two women victims were in court as Ms Aurora said: “Mr Jackson has asked me to apologise. He accepts what he did and the consequences to the people concerned.”

She said he had no independent recollection of the events either as a result of alcohol or trying to black them out of his memory.

She asked the judge to pass a suspended sentence because of Jackson’s “complex psychological, mental health and alcohol issues.”

But Judge Bright jailed him, saying: “You must have known what you were doing was wrong. It has had a very profound lifelong effect on the victims. It demands an immediate custodial sentence.” Jackson must also register as a sex offender for 10 years.